Passenger compartment heating and cooling are provided in most automobiles. In internal combustion engines of automobiles, an engine driven compressor runs a vapor compression air conditioning system for summer operation. In the winter, waste heat of combustion is used for heating the passenger compartment. In future vehicles designed to decrease automobile emissions, the source of propulsion energy is commonly an electric storage device, such as a battery. The amount of energy that can be stored in the currently available battery is limited, therefore there is a need to minimize the use of stored energy for other uses such as passenger thermal comfort.
Present air conditioning systems in vehicles are air-coupled, i.e., the condenser is cooled by air and the evaporator is heated by air. Because the passenger compartment needs to be heated in the winter and cooled in the summer, the heat exchanger located in a heating, ventilating and air conditioning (HVAC) module should operate as an evaporator in the summer and a condenser in the winter. Similarly, the heat exchanger located at the front end should operate as an evaporator in the winter and a condenser in the summer. This necessitates the reversal of the flow of refrigerants through the system. Furthermore, due to the close coupling of the refrigerant circuit and the respective air streams, there is no flexibility in the location of the heat exchangers. In other words, one of the refrigerant heat exchangers must necessarily be at the front end to interact with ram air, while the other must be in the HVAC module.
Electronic heat exchange systems are known outside of the application of vehicles. One such system is disclosed in U.S. Pat. No. 4,248,056 issued Feb. 3, 1981 in the name of Beacham. The patent discloses a heat reclaimer for a heat pump. The heat reclaimer is coiled about the condenser in heat transfer relationship therewith and absorbs heat from the compressor by circulating cooling fluid therethrough. The reclaiming circuit is connected into a fluid circulating loop which is used to supply heat to the evaporator coil of the heat pump.
German patent no. 3042983 issued Sep. 30, 1982 discloses a hot water tank for a heat pump which contains two double walled condenser coils with hot water passing through the inner tubes. Within the hot water tank, there are two condensers consisting of a double walled tube wound into a coil. The inner tube is connected to the hot water supply line halfway up the tank and discharges through a vertical tube inside the tank with one branch connected to the top of the bottom coil and a second branch discharging into the bottom of the tank.
The problem with the prior art, is that it is not readily nor efficiently adaptable to vehicle heat exchange systems for heating and cooling a passenger compartment.